shithub: libvpx

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Reintroduce fix for max qindex calculation of a gf interval

This reintroduces the fix:
  https://chromium-review.googlesource.com/c/422807/
and later reverted here:
  https://chromium-review.googlesource.com/c/447843/

BUG=webm:1355

This time behind a compile time flag :

configure --disable-always_adjust_bpm
configure --enable-always_adjust_bpm

This should make side by side testing easier and let users of the
lib pick which way they want to go.

Change-Id: I7d7b37b83015dc001810af84c132cbc1e71ba8d6

--- a/configure

+++ b/configure

@@ -319,6 +319,7 @@

     better_hw_compatibility

     experimental

     size_limit

+    always_adjust_bpm

     ${EXPERIMENT_LIST}

 "

 CMDLINE_SELECT="

@@ -378,6 +379,7 @@

     better_hw_compatibility

     vp9_highbitdepth

     experimental

+    always_adjust_bpm

 "

 process_cmdline() {

--- a/vp9/encoder/vp9_firstpass.c

+++ b/vp9/encoder/vp9_firstpass.c

@@ -1586,6 +1586,7 @@

   const RATE_CONTROL *const rc = &cpi->rc;

   const VP9EncoderConfig *const oxcf = &cpi->oxcf;

   TWO_PASS *const twopass = &cpi->twopass;

+  double last_group_rate_err;

   // Clamp the target rate to VBR min / max limts.

   const int target_rate =

@@ -1594,6 +1595,18 @@

   noise_factor = fclamp(noise_factor, NOISE_FACTOR_MIN, NOISE_FACTOR_MAX);

   inactive_zone = fclamp(inactive_zone, 0.0, 1.0);

+// TODO(jimbankoski): remove #if here or below when this has been

+// well tested.

+#if CONFIG_ALWAYS_ADJUST_BPM

+  // based on recent history adjust expectations of bits per macroblock.

+  last_group_rate_err =

+      (double)twopass->rolling_arf_group_actual_bits /

+      DOUBLE_DIVIDE_CHECK((double)twopass->rolling_arf_group_target_bits);

+  last_group_rate_err = VPXMAX(0.25, VPXMIN(4.0, last_group_rate_err));

+  twopass->bpm_factor *= (3.0 + last_group_rate_err) / 4.0;

+  twopass->bpm_factor = VPXMAX(0.25, VPXMIN(4.0, twopass->bpm_factor));

+#endif

+

   if (target_rate <= 0) {

     return rc->worst_quality;  // Highest value allowed

   } else {

@@ -1604,11 +1617,13 @@

     const int active_mbs = (int)VPXMAX(1, (double)num_mbs * active_pct);

     const double av_err_per_mb = section_err / active_pct;

     const double speed_term = 1.0 + 0.04 * oxcf->speed;

-    double last_group_rate_err;

     const int target_norm_bits_per_mb =

         (int)(((uint64_t)target_rate << BPER_MB_NORMBITS) / active_mbs);

     int q;

+// TODO(jimbankoski): remove #if here or above when this has been

+// well tested.

+#if !CONFIG_ALWAYS_ADJUST_BPM

     // based on recent history adjust expectations of bits per macroblock.

     last_group_rate_err =

         (double)twopass->rolling_arf_group_actual_bits /

@@ -1616,6 +1631,7 @@

     last_group_rate_err = VPXMAX(0.25, VPXMIN(4.0, last_group_rate_err));

     twopass->bpm_factor *= (3.0 + last_group_rate_err) / 4.0;

     twopass->bpm_factor = VPXMAX(0.25, VPXMIN(4.0, twopass->bpm_factor));

+#endif

     // Try and pick a max Q that will be high enough to encode the

     // content at the given rate.

@@ -2595,6 +2611,12 @@

         group_av_noise, vbr_group_bits_per_frame);

     twopass->active_worst_quality =

         (tmp_q + (twopass->active_worst_quality * 3)) >> 2;

+

+#if CONFIG_ALWAYS_ADJUST_BPM

+    // Reset rolling actual and target bits counters for ARF groups.

+    twopass->rolling_arf_group_target_bits = 0;

+    twopass->rolling_arf_group_actual_bits = 0;

+#endif

   }

   // Context Adjustment of ARNR filter strength

@@ -2629,10 +2651,11 @@

     // Default to starting GF groups at normal frame size.

     cpi->rc.next_frame_size_selector = UNSCALED;

   }

-

+#if !CONFIG_ALWAYS_ADJUST_BPM

   // Reset rolling actual and target bits counters for ARF groups.

   twopass->rolling_arf_group_target_bits = 0;

   twopass->rolling_arf_group_actual_bits = 0;

+#endif

 }

 // Threshold for use of the lagging second reference frame. High second ref